Lower Levels = more Magic Stones?

I heard somewhere that you get more Magic Stones in the end if you get the chars at low Levels; is that true?

No, the number of Magic Stones per level is fixed. Speed, Strength, Magic and Spirit, however, are a different matter. The better stat-boosting equipment you have on when you level up, the higher those four stats will be. That's why it may be best to stay at low levels until you can access the high-level equipment.